We Keep Coding

unable to load a javafx scene

I have a problem with loading a file. I'm trying to load the scene "areaView.fxml" with the following code:
public class View extends Application {
public static void main(String[] args) {
launch(args);
}
#Override
public void start(Stage primaryStage) throws IOException {
FXMLLoader loader = new FXMLLoader(getClass().getResource("/resources/areaView.fxml"));
Parent root = loader.load();
Scene scene = new Scene(root);
primaryStage.setScene(scene);
primaryStage.show();
}}
But when I launch I get an InvocationTargetException..
For information i'm on windows and the absolute path of the file is: C:\Users\pierr\Desktop\Yves\resources\areaView.fxml
It's probably a stupid mistake but I've been stuck on it for quite some time.... I'm almost sure it's related to the "/" but all my attempts to fix it have failed...
Thank you in advance
EDIT :
Here the full stack tace
EDIT n°2
Very strange thing when I test this:
System.out.println(getClass().getResource("").toString());
I get this : file:/C:/Users/pierr/Desktop/Yves/out/production/Yves/view/
When I would have imagined getting this: file:/C:/Users/pierr/Desktop/Yves/
If i move my file to file:/C:/Users/pierr/Desktop/Yves/out/production/Yves/view/ it works but in fact this solution is not satisfactory

By default your resources folder should be under projectName/src/main/resources.
So in your case: C:\Users\pierr\Desktop\Yves\src\main\resources\areaView.fxml.
In such case .getResource("areaView.fxml") should be sufficient.
Just keep in mind that if you move your fxml to a different folder or you call getResource from a different folder than src/main/java you will have to change the relative path that you pass to the method.

How to make Combobox retain its selected value in JavaFx while calling from another class? [duplicate]

I would like to communicate with a FXML controller class at any time, to update information on the screen from the main application or other stages.
Is this possible? I havent found any way to do it.
Static functions could be a way, but they don't have access to the form's controls.
Any ideas?

You can get the controller from the FXMLLoader
FXMLLoader fxmlLoader = new FXMLLoader();
Pane p = fxmlLoader.load(getClass().getResource("foo.fxml").openStream());
FooController fooController = (FooController) fxmlLoader.getController();
store it in your main stage and provide getFooController() getter method.
From other classes or stages, every time when you need to refresh the loaded "foo.fxml" page, ask it from its controller:
getFooController().updatePage(strData);
updatePage() can be something like:
// ...
#FXML private Label lblData;
// ...
public void updatePage(String data){
lblData.setText(data);
}
// ...
in the FooController class.
This way other page users do not bother about page's internal structure like what and where Label lblData is.
Also look the https://stackoverflow.com/a/10718683/682495. In JavaFX 2.2 FXMLLoader is improved.

Just to help clarify the accepted answer and maybe save a bit of time for others that are new to JavaFX:
For a JavaFX FXML Application, NetBeans will auto-generate your start method in the main class as follows:
#Override
public void start(Stage stage) throws Exception {
Parent root = FXMLLoader.load(getClass().getResource("FXMLDocument.fxml"));
Scene scene = new Scene(root);
stage.setScene(scene);
stage.show();
}
Now, all we need to do to have access to the controller class is to change the FXMLLoader load() method from the static implementation to an instantiated implementation and then we can use the instance's method to get the controller, like this:
//Static global variable for the controller (where MyController is the name of your controller class
static MyController myControllerHandle;
#Override
public void start(Stage stage) throws Exception {
//Set up instance instead of using static load() method
FXMLLoader loader = new FXMLLoader(getClass().getResource("FXMLDocument.fxml"));
Parent root = loader.load();
//Now we have access to getController() through the instance... don't forget the type cast
myControllerHandle = (MyController)loader.getController();
Scene scene = new Scene(root);
stage.setScene(scene);
stage.show();
}

Another solution is to set the controller from your controller class, like so...
public class Controller implements javafx.fxml.Initializable {
#Override
public void initialize(URL location, ResourceBundle resources) {
// Implementing the Initializable interface means that this method
// will be called when the controller instance is created
App.setController(this);
}
}
This is the solution I prefer to use since the code is somewhat messy to create a fully functional FXMLLoader instance which properly handles local resources etc
#Override
public void start(Stage stage) throws Exception {
Parent root = FXMLLoader.load(getClass().getResource("/sample.fxml"));
}
versus
#Override
public void start(Stage stage) throws Exception {
URL location = getClass().getResource("/sample.fxml");
FXMLLoader loader = createFXMLLoader(location);
Parent root = loader.load(location.openStream());
}
public FXMLLoader createFXMLLoader(URL location) {
return new FXMLLoader(location, null, new JavaFXBuilderFactory(), null, Charset.forName(FXMLLoader.DEFAULT_CHARSET_NAME));
}

On the object's loading from the Main screen, one way to pass data that I have found and works is to use lookup and then set the data inside an invisible label that I can retrieve later from the controller class. Like this:
Parent root = FXMLLoader.load(me.getClass().getResource("Form.fxml"));
Label lblData = (Label) root.lookup("#lblData");
if (lblData!=null) lblData.setText(strData);
This works, but there must be a better way.

call methods inside controller from a different class javafx [duplicate]

I would like to communicate with a FXML controller class at any time, to update information on the screen from the main application or other stages.
Is this possible? I havent found any way to do it.
Static functions could be a way, but they don't have access to the form's controls.
Any ideas?

You can get the controller from the FXMLLoader
FXMLLoader fxmlLoader = new FXMLLoader();
Pane p = fxmlLoader.load(getClass().getResource("foo.fxml").openStream());
FooController fooController = (FooController) fxmlLoader.getController();
store it in your main stage and provide getFooController() getter method.
From other classes or stages, every time when you need to refresh the loaded "foo.fxml" page, ask it from its controller:
getFooController().updatePage(strData);
updatePage() can be something like:
// ...
#FXML private Label lblData;
// ...
public void updatePage(String data){
lblData.setText(data);
}
// ...
in the FooController class.
This way other page users do not bother about page's internal structure like what and where Label lblData is.
Also look the https://stackoverflow.com/a/10718683/682495. In JavaFX 2.2 FXMLLoader is improved.

Just to help clarify the accepted answer and maybe save a bit of time for others that are new to JavaFX:
For a JavaFX FXML Application, NetBeans will auto-generate your start method in the main class as follows:
#Override
public void start(Stage stage) throws Exception {
Parent root = FXMLLoader.load(getClass().getResource("FXMLDocument.fxml"));
Scene scene = new Scene(root);
stage.setScene(scene);
stage.show();
}
Now, all we need to do to have access to the controller class is to change the FXMLLoader load() method from the static implementation to an instantiated implementation and then we can use the instance's method to get the controller, like this:
//Static global variable for the controller (where MyController is the name of your controller class
static MyController myControllerHandle;
#Override
public void start(Stage stage) throws Exception {
//Set up instance instead of using static load() method
FXMLLoader loader = new FXMLLoader(getClass().getResource("FXMLDocument.fxml"));
Parent root = loader.load();
//Now we have access to getController() through the instance... don't forget the type cast
myControllerHandle = (MyController)loader.getController();
Scene scene = new Scene(root);
stage.setScene(scene);
stage.show();
}

Another solution is to set the controller from your controller class, like so...
public class Controller implements javafx.fxml.Initializable {
#Override
public void initialize(URL location, ResourceBundle resources) {
// Implementing the Initializable interface means that this method
// will be called when the controller instance is created
App.setController(this);
}
}
This is the solution I prefer to use since the code is somewhat messy to create a fully functional FXMLLoader instance which properly handles local resources etc
#Override
public void start(Stage stage) throws Exception {
Parent root = FXMLLoader.load(getClass().getResource("/sample.fxml"));
}
versus
#Override
public void start(Stage stage) throws Exception {
URL location = getClass().getResource("/sample.fxml");
FXMLLoader loader = createFXMLLoader(location);
Parent root = loader.load(location.openStream());
}
public FXMLLoader createFXMLLoader(URL location) {
return new FXMLLoader(location, null, new JavaFXBuilderFactory(), null, Charset.forName(FXMLLoader.DEFAULT_CHARSET_NAME));
}

On the object's loading from the Main screen, one way to pass data that I have found and works is to use lookup and then set the data inside an invisible label that I can retrieve later from the controller class. Like this:
Parent root = FXMLLoader.load(me.getClass().getResource("Form.fxml"));
Label lblData = (Label) root.lookup("#lblData");
if (lblData!=null) lblData.setText(strData);
This works, but there must be a better way.

Java Form problems

I've recently delved into JavaFX as a C# developer. One thing I noticed in Java is that you're not spoon fed the way Visual Studio/Microsoft spoonfeed us.
So. When I was creating a form using the scene builder for IntelliJ Idea on JavaFX. I inherited "Stage" for my controller class and created a void called load that will load the instance of the scene from the FXML file. Therefore when I call load() from the Main entry point or anywhere it will load the fxml file and show.
LoginController frmLogin = new LoginController();
frmLogin.load();
The problem is that it works and it does't work.
Here's my code.
Main.Java
public class Main extends Application
{
#Override
public void start(Stage primaryStage) throws Exception
{
LoginController frmLogin = new LoginController();
frmLogin.load();
}
public static void main(String[] args)
{
Application.launch(args);
}
}
LoginController.Java
public class LoginController extends Stage
{
#FXML
private TextField txtUsername;
#FXML
private TextField txtPassword;
#FXML
private void btnLogin_Clicked(ActionEvent e) throws Exception
{
if (txtUsername.getText().equals("admin") && txtPassword.getText().equals("pass"))
{
Messagebox.Show("Correct Login!");
this.show(); //The problem occurs here!
}
else
{
Messagebox.Show("Incorrect Login");
}
}
public void load() throws Exception
{
Parent root = FXMLLoader.load(getClass().getResource("frmLogin.fxml"));
this.setScene(new Scene(root));
this.setTitle("JavaFX GUI");
this.setResizable(false);
this.initModality(Modality.APPLICATION_MODAL);
this.show();
}
}
Here's a GIF of the problem.
http://i.imgur.com/0hOG76M.gif
I want to know why when I call .show() it shows a blank for?
Any help would be appreicated.

Solution
Don't inherit Stage in your Controller.
JavaFX will implicitly create a Stage for your application and pass it to your application (the primaryStage parameter in your application start method).
Sample
Here is a quick update which should work. Another alternative for this is to factor out the stage management as in James's answer.
public class Main extends Application
{
#Override
public void start(Stage primaryStage) throws Exception
{
Parent root = FXMLLoader.load(getClass().getResource("frmLogin.fxml"));
primaryStage.setScene(new Scene(root));
primaryStage.setTitle("JavaFX GUI");
primaryStage.setResizable(false);
primaryStage.show();
}
public static void main(String[] args)
{
Application.launch(args);
}
}
. . .
public class LoginController
{
#FXML
private TextField txtUsername;
#FXML
private TextField txtPassword;
#FXML
private void btnLogin_Clicked(ActionEvent e) throws Exception
{
if (txtUsername.getText().equals("admin") && txtPassword.getText().equals("pass"))
{
Messagebox.Show("Correct Login!");
}
else
{
Messagebox.Show("Incorrect Login");
}
}
}
Aside: I am not sure what your MessageBox class is, but JavaFX 8u40 has a built-in Alert dialog box for standard message box style functionality, so that would be the preferred method to do that.

It looks like you have confused the different pieces that make up the application.
The FXML typically represents the "view"; i.e. the portion of the UI that is visible. It defines what controls are displayed and how they are laid out.
The controller implements the logic that is connected to (controls) the view. So it typically processes user input and updates the view in various ways.
A Stage is a window.
So, I don't think it really makes sense that your controller is a Stage. There are some scenarios where you might make a controller a subclass of a UI element, but those are somewhat advanced uses of JavaFX, and even then you would typically subclass a layout pane, not a Stage.
Here's roughly what happens when you call load on an FXMLLoader:
The FXMLLoader creates a hierarchy of Nodes (UI elements) corresponding to the elements defined in the FXML file
If the FXML file defines a fx:controller attribute in its root element, the FXMLLoader constructs a new instance of that class. It then injects any elements with fx:id attributes into fields in that controller instance with names matching the fx:id values. It also registers any event handlers mapping to methods in the controller instance.
The FXMLLoader's load() method returns the object corresponding to the root element of the FXML file.
So, in your code, you actually end up with two LoginController instances. You create one yourself in the start() method. You then call load() on that instance. That method calls load(...) on an FXMLLoader (via the really ugly static load method). Calling FXMLLoader.load(...) then causes the FXMLLoader to create an instance of the class declared in fx:controller. I'm guessing (you didn't show the FXML code) that class is also LoginController. So that is the second instance.
Now what happens, is that you get a reference to the UI element from FXMLLoader.load(). You put that in a Scene, and set the Scene in the LoginController, which - unusually - is a Stage. Then you make the Stage appear on the screen with show(). Note this happens in the instance you created in the start method.
When the user presses the button that has btnLogin_Clicked registered as its handler, the handler method is invoked on the controller instance: the one created by the FXMLLoader. That instance never had a Scene set, so when you then call this.show() it shows that instance of the LoginController (which, again, is a Stage). Since it never had its scene set, you see a blank window.
It's not actually clear to me what you intend with the call to this.show() in btnLogin_Clicked anyway. Assuming you thought this was the same Stage you had created from the start(...) method, that Stage is already showing.
The typical pattern is that you use the primaryStage that is passed to the start(...) method, and set a scene in that and show it. So you'd do something like:
public class Main extends Application
{
#Override
public void start(Stage primaryStage) throws Exception
{
Parent root = FXMLLoader.load(getClass().getResource("frmLogin.fxml"));
primaryStage.setScene(new Scene(root));
primaryStage.setTitle("JavaFX GUI");
primaryStage.setResizable(false);
primaryStage.initModality(Modality.APPLICATION_MODAL);
primaryStage.show();
}
public static void main(String[] args)
{
Application.launch(args);
}
}
and then the controller is just a controller: it just handles the logic:
public class LoginController
{
#FXML
private TextField txtUsername;
#FXML
private TextField txtPassword;
#FXML
private void btnLogin_Clicked(ActionEvent e) throws Exception
{
if (txtUsername.getText().equals("admin") && txtPassword.getText().equals("pass"))
{
Messagebox.Show("Correct Login!");
// I don't really know what you were trying to do here
// but if you need a reference to the window containing the
// associated fxml elements, you can get it from one of those
// elements:
Stage stage = (Stage) txtUsername.getScene().getWindow();
//this.show(); //The problem occurs here!
}
else
{
Messagebox.Show("Incorrect Login");
}
}
}
Typically what you want to do when the user has successfully logged in, is to display something new in the current window. The simplest way to do this is just to set the root of the current scene to the content of a different FXML file. For example:
public class LoginController
{
#FXML
private TextField txtUsername;
#FXML
private TextField txtPassword;
#FXML
private void btnLogin_Clicked(ActionEvent e) throws Exception
{
if (txtUsername.getText().equals("admin") && txtPassword.getText().equals("pass"))
{
Messagebox.Show("Correct Login!");
Scene currentScene = txtUsername.getScene();
Parent root = FXMLLoader.load(getClass().getResource("Main.fxml"));
currentScene.setRoot(root);
// resize window:
currentScene.getWindow().sizeToScene();
}
else
{
Messagebox.Show("Incorrect Login");
}
}
}
Here Main.fxml defines the main application the user sees, having successfully logged in, and defines its own controller class, etc.

MVC Pattern in JavaFX With Scene Builder

I'm new to JavaFX and am struggling to create a proper MVC architecture given my current setup. I clicked together a UI using Scene Builder and designated a Controller class.
Startup:
public class Portal extends Application {
public static void main(String[] args) {
launch(args);
}
#Override
public void start(Stage stage) throws Exception {
Parent root = FXMLLoader.load(getClass().getResource("PortalUI.fxml"));
stage.setTitle("Portal");
stage.setScene(new Scene(root));
stage.show();
}
}
And the Controller class contains the rest of the code.
public class AccommodationPortalView implements Initializable {
#Override
public void initialize(URL url, ResourceBundle resources) {
// Work here.
}
}
My professor asked that I further separate the concerns and responsibilities of this application. The Controller is not only managing state and talking with the backend, but also updating the View.
My first response was to let the Controller class become the View and create two other classes for the Controller and Model.
However, I'm at a loss at how to connect these pieces. I never need to instantiate the View, so there is no View instance that I can pass to my Controller, for example. Next, I tried making them all singletons and simply letting Controller fetch them at runtime, but that gives me an error.
public class Portal extends Application {
public static void main(String[] args) {
launch(args);
}
#Override
public void start(Stage stage) throws Exception {
Parent root = FXMLLoader.load(getClass().getResource("PortalUI.fxml"));
stage.setTitle("Portal");
stage.setScene(new Scene(root));
stage.show();
// Controller gets a View and Model instance in initialize();
// Error: Instantiation and Runtime Exception...
PortalController.INSTANCE.initialize();
}
}
How do I properly set-up an MVC pattern using my current configuration? Is a different architecture required?

Your,
-- View is a primary Stage provided by the JavaFX platform at start up. This stage has the only Scene (you have created and set) which in turn has a parent node content root (your variable). This root node is set by FXMLLoader and represents the layout/node structure defined in the "PortalUI.fxml" file.
In other words Stage -> Scene -> PortalUI.fxml(root) will define the view part.
-- Controller is the class that implements Initializable and that you specified in your PortalUI.fxml file with fx:controller=" " attribute. The class you have specified there (PortalController I suppose) will be created and invoked its initialize() method by the FXMLLoader. Namely the Controller will be created when the PortalUI.fxml file is loaded, so you don't need to create and initialize it yourself. To get the created/initialized instance of the controller from the FXMLLoader look the Accessing FXML controller class.
-- Model is the underlying data structure stored and managed by the controller. It can be anything representing the "data". For example, Person, PortalInfo etc. classes.